MTS Series 505 SilentFlo Hydraulic Power Unit Model 505-30 - Manual (Page 61)

Replacing the Return Line Filter
Model 505.20 - 505.30 SilentFlo™ HPU Maintenance 61
3. Open the filler cap and check the smell of the hydraulic fluid. Burnt-
smelling hydraulic fluid can indicate a chemical breakdown.
If you detect a distinct change in the smell of hydraulic fluid, have it
chemically analyzed by the manufacturer.
4. Keep records of the maximum reservoir temperature.
High operating temperatures can cause the fluid to break down. If your
records indicate a pattern of overheating, consult your MTS Field Service
Engineer to determine if changes or adjustments to your hydraulic system
are required.
5. Check and adjust the hydraulic fluid delivery system so that:
• Hydraulic fluid temperature stabilizes within the parameters given in
the “Specifications” table when the HPU is operating at high pressure.
• Pressure line reading is maintained at 21 MPa (3000 psi) maximum
static value.
• Maximum drain line back pressure is limited to 0.1 MPa (15 psi).
If you need to adjust the water-regulating valve, overtemperature switch or
pressure control valves, refer to the appropriate procedure.
Replacing the Return Line Filter
The filter element of the HPU should be replaced for the following reasons:
• When the dirty-filter indicator lights
• Whenever the hydraulic fluid is changed
• The filter manufacturer’s recommended maximum interval has passed
(1000 hours or 6 months)
Prerequisite
You will need a filter element (MTS part number 010-053-349) or a filter kit
(MTS part number 100-078-099).
Procedure
To change the filter element:
Note The dirty-filter indicator may light when the HPU is first started due to low
hydraulic fluid temperature. When the HPU is at normal operating
temperature, recheck the indicator to determine if the element actually
needs replacement.
1. Turn off the HPU.